AB0655 Clinical and immunological features of a Portuguese cohort of Mixed Connective Tissue Disease
Authors: F. Guimarães, M. Silvério-António, J. Martinho, A. T. Melo, D. Santos Oliveira, J. M. Pestana Lopes, A. Saraiva, L. Gago, A. M. Gomes Correia, A. L. Fernandes, S. P. Dinis, R. Nicolau, S. P. Silva, C. Costa, T. Beirão, A. Furtado, P. M. Azevedo Abreu, N. Khmelinskii, C. Afonso, D. Peixoto
Journal: Annals of the Rheumatic Diseases (2022)

Background Various nationwide studies have been already published to better understand Mixed Connective Tissue Disease (MCTD) (1,2). However, Portuguese data is not available. Objectives To characterize clinical and immunological features of a Portuguese cohort of patients with MCTD. Methods Retrospective, multicenter study including adult-onset patients with clinical diagnosis of MCTD and fulfilling at least one of the following classification criteria: Sharp, Kasukawa, Alarcón-Segovia or the Kahn’s criteria. Positivity to other autoantibodies besides anti-U1-RNP were allowed. SPSS was used for statistical analysis and significance level was defined as 2-sided p &lt;.05. Results A total of 98 patients were included, with a mean age at diagnosis and disease duration of 40.5±13.7 and 7.0±6.5 years, respectively. Most patients were female (87.8%) and Caucasian (70.4%). Raynaud’s phenomenon (96.9%), arthralgia/arthritis (94.9/74.5%) and puffy fingers (60.2%) were the most common and early manifestations. Gastroesophageal (GE), respiratory and muscular involvement were also prevalent, mostly during the follow up, affecting 30.6%, 34.7% and 43.9% of the patients, respectively. Clinical and immunological characteristics are described in Table 1. Males were older at symptom’s onset (65.0 VS 46.7, p =.035), having more respiratory involvement (OR=4.5, 95% CI 1.3-16.4), and positivity to anti-ACPA (OR=20.0, 95% CI: 3.1-129.4). GE involvement occurred more often in Caucasian patients (OR=3.8; 95% CI: 1.0-14.1), while anemia of chronic diseases (OR=2.7; 95% CI: 1.0-7.2), myositis (OR=3.6; 95% CI: 1.3-9.9) and constitutional symptoms (OR=3.2; 95% CI: 1.2-8.3) were more frequent in Afro-American patients, whose were also younger at disease (34.1 VS 50.6, p =.01). After a median follow-up time of 4 (IQR 8) years, 4 deaths occurred (4.1%), mostly (75%) due to infectious complications. Table 1. Clinical and immunological characteristics Clinical Manifestations At presentation Follow-up Mucocutaneous system Raynaud’s phenomenon, n (%) 85 (86.7) 95 (96.9) Puffy hands, n (%) 48 (49.0) 59 (60.2) SSc-like, n (%) 43 (44.8) 59 (60.8) SLE-like, n (%) 28 (28.9) 35 (35.7) Musculoskeletal system Arthralgia/Arthritis, n (%)/n (%) 81 (82.7) / 56 (57.1) 93 (94.9) / 73 (74.5) Myositis, n (%) 26 (25.6) 43 (43.9) Hematological system, n (%) 46 (46.9) 70 (71.4) Respiratory system, n (%) 14 (14.3) 34 (34.7) Cardiovascular system 3 (3.1) 4 (4.1) Pulmonary hypertension* 2 (2.0) 15 (15.3) Gastroesophageal involvement, n (%) 11 (11.2) 30 (30.6) Renal involvement, n (%) 2 (2.0) 10 (10.2) Neurological involvement, n (%) 6 (6.3) 14 (14.3) Constitutional symptoms, n (%) 26 (26.5) 30 (30.6) Immunological characteristics Anti-dsDNA, n (%) 21 (21.4) Anti-smith antibody, n (%) 21 (21.4) Anti-Ro/SSA, n (%) 31 (31.6) Anti-La/SSB, n (%) 7 (7.1) Anti-centromere, n (%) 3 (4.1) Rheumatoid Factor, n (%) 39 (39.8) Anti- anti-citrullinated protein antibodies, n (%) 6 (6.1) Antiphospholipid antibodies, n (%) 7 (7.1) Myositis antibodies, n (%) 9 (9.2) Complement activation, n (%) 27 (27.6) Hypergammaglobulinemia, n (%) 51 (52.0) Legend: Anti-dsDNA: anti-double stranded deoxyribonucleic acid antibody; SLE: systemic lupus erythematosus, SSc: systemic sclerosis. *No information regarding cardiac catheterism, then compatible alterations in the echocardiogram. Conclusion Raynaud’s phenomenon, puffy fingers and arthritis were the most common manifestations in Portuguese patients, with similar proportions found in literature (1,2). However, we reported some differences in mucocutaneous, renal and serosa involvement and higher prevalence of probable pulmonary hypertension (1,2), which may be explained by the heterogeneity of the inclusion criteria. Except for respiratory, myositis, GE and constitutional symptoms, there were no differences regarding gender and ethnicity. Here, we characterize the largest cohort of MCTD in Portugal. References [1]Cappelli S, et al. Semin Arthritis Rheum. 2012 Feb;41(4):589–98. [2]Alves MR et al. Clin Exp Med. 2020 May;20(2):159–66. Disclosure of Interests None declared